The invention relates to a rotation rate sensor having a vibration gyro with circuits which are used for operation of the vibration gyro and for emission of a rotation rate signal and which access variable data, having a nonvolatile memory which can be written to and in which the data is stored, and having means for reading the data from the nonvolatile memory after switching on the rotation rate sensor, with the data being subdivided into groups on the basis of its use, and measures for data protection being taken for in each case one group.
By way of example, U.S. Pat. No. 5,226,321 discloses rotation rate sensors in which a vibration gyro is excited on two axes which are aligned radially with respect to a major axis, for which purpose a primary and a secondary control loop having appropriate transducers are provided on the vibration gyro. These control loops may include various analog and digital circuits, with the analog circuits and the vibration gyro having tolerances, so that adjustment is necessary, at least during the production of the rotation rate sensor. The individual circuits then access the stored data during subsequent operation.
Furthermore, EP 1 189 025 A2 and U.S. Pat. No. 5,313,835 have disclosed data such as this being stored in an EEPROM. For safety reasons, the data is stored in a duplicated (redundant) form in EP 1 189 025 A2, so that the correctness of the data that is read can be checked by comparison. In addition, only one data storage process is provided during the production of the rotation rate sensor.
In the case of a rotation rate sensor which has been disclosed in U.S. Pat. No. 5,826,204, a non-volatile memory is provided in an associated electronic controller and has written to it table values which change as the “learning success” of the controller progresses. There is therefore fundamentally a risk that, in poor circumstances, incorrect data may also be written to the volatile memory.
Furthermore, it may be necessary to match characteristics of the rotation rate sensor to the respectively intended purpose, for example by presetting parameter sets for filters.